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Quantum Key Distribution is a quantum communication technique in which random numbers are encoded on quantum systems, usually photons, and sent from one party, Alice, to another, Bob. Using the data sent via the quantum signals,…

Quantum Physics · Physics 2014-09-09 T. C. Ralph , N. Walk

In realistic continuous variable quantum key distribution protocols, an eavesdropper may exploit the additional Gaussian noise generated during transmission to mask her presence. We present a theoretical framework for a post-selection based…

In secure quantum communication protocols, a set of single qubits prepared using 2 or more mutually unbiased bases or a set of $n$-qubit ($n\geq2$) entangled states of a particular form are usually used to form a verification string which…

Quantum Physics · Physics 2022-06-10 Rishi Dutt Sharma , Kishore Thapliyal , Anirban Pathak , Alok Kumar Pan , Asok De

We address side-channel leakage in a trusted preparation station of continuous-variable quantum key distribution with coherent and squeezed states. We consider two different scenaria: multimode Gaussian modulation, directly accessible to an…

Quantum Physics · Physics 2017-12-13 Ivan Derkach , Vladyslav C. Usenko , Radim Filip

We investigate the security of continuous-variable (CV) quantum key distribution (QKD) using coherent states in the presence of quadrature excess noise. We consider an eavesdropping attack which uses a linear amplifier and beam splitter.…

Quantum Physics · Physics 2009-11-11 Ryo Namiki , Takuya Hirano

A secret key shared through quantum key distribution between two cooperative players is secure against any eavesdropping attack allowed by the laws of physics. Yet, such a key can be established only when the quantum channel error rate due…

Quantum Physics · Physics 2007-05-23 H. F. Chau

We give a proof that entanglement purification, even with noisy apparatus, is sufficient to disentangle an eavesdropper (Eve) from the communication channel. In the security regime, the purification process factorises the overall initial…

Quantum Physics · Physics 2009-11-07 Hans Aschauer , Hans J. Briegel

Quantum secure direct communication is one of the important mode of quantum communication, which sends secret information through a quantum channel directly without setting up a prior key. Over the past decade, numerous protocols have been…

Quantum Physics · Physics 2017-06-13 Jianyong Hu , Mingyong Jing , Peng Zhang , Qiangqiang Zhang , Huifang Hou , Liantuan Xiao , Suotang Jia

Information-theoretically secure communications are possible when channel noise is usable and when the channel has an intrinsic characteristic that a legitimate receiver (Bob) can use the noise more advantageously than an eavesdropper…

Cryptography and Security · Computer Science 2018-03-15 Tatsuya Tomaru

We consider a strategic problem of the Evesdropping to quantum key distribution. Evesdropper hopes to obtain the maxium information given the disturbance to the qubits is often For this strategy, the optimized individual attack have been…

Quantum Physics · Physics 2007-05-23 Wang Xiang-bin

We propose efficient-phase-encoding protocols for continuous-variable quantum key distribution using coherent states and postselection. By these phase encodings, the probability of basis mismatch is reduced and total efficiency is…

Quantum Physics · Physics 2008-09-29 Ryo Namiki , Takuya Hirano

We introduce noise-adaptive quantum key distribution (QKD) protocols, in which the honest parties optimize the encoding (state preparation) and decoding (measurement basis) operations according to the noise models affecting the honest…

Quantum Physics · Physics 2026-05-28 Abinash Kar , Ayan Patra , Aditi Sen De , Tamoghna Das

A new and simple quantum key distribution scheme based on the quantum intensity correlation of optical twin beams and the directly local measurements of intensity noise of single optical beam is presented and experimentally demonstrated.…

Quantum Physics · Physics 2007-05-23 Xiaojun Jia , Xiaolong Su , Qing Pan , Kunchi Peng , Changde Xie

A quantum key distribution protocol based on entanglement swapping is proposed. Through choosing particles by twos from the sequence and performing Bell measurements, two communicators can detect eavesdropping and obtain the secure key.…

Quantum Physics · Physics 2007-05-23 Fei Gao , Fenzhuo Guo , Qiaoyan Wen , Fuchen Zhu

A continuous key distribution scheme is proposed that relies on a pair of canonically conjugate quantum variables. It allows two remote parties to share a secret Gaussian key by encoding it into one of the two quadrature components of a…

Quantum Physics · Physics 2009-11-06 N. J. Cerf , M. Levy , G. Van Assche

Security of a continuous-variable quantum key distribution protocol based on noisy coherent states and channel is analyzed. Assuming the noise of coherent states is induced by Fred, a neutral party relative to others, we prove that the…

Quantum Physics · Physics 2015-05-13 Yong Shen , Jian Yang , Hong Guo

In practical quantum key distribution (QKD) system, the state preparation and measurement are imperfect comparing with the ideal BB84 protocol, which are always state-dependent in practical realizations. If the state-dependent imperfections…

Quantum Physics · Physics 2011-12-21 Hong-Wei Li , Zhen-Qiang Yin , Zheng-Fu Han , Wan-Su Bao , Guang-Can Guo

We present a new technique for proving the security of quantum key distribution (QKD) protocols. It is based on direct information-theoretic arguments and thus also applies if no equivalent entanglement purification scheme can be found.…

Quantum Physics · Physics 2009-11-11 R. Renner , N. Gisin , B. Kraus

Quantum secret sharing (QSS) enables a dealer to securely distribute keys to multiple players. Device-independent (DI) QSS can resist all possible attacks from practical imperfect devices and provide QSS the highest level of security in…

We consider the private classical capacity of a quantum wiretap channel, where the users (sender Alice, receiver Bob, and eavesdropper Eve) have access to the resource of a shared quantum state, additionally to their channel inputs and…

Quantum Physics · Physics 2024-09-25 Minglai Cai , Andreas Winter